The triple Higgs coupling: A new probe of low-scale seesaw models

TL;DR

This paper investigates how heavy neutrinos in low-scale seesaw models can significantly alter the triple Higgs coupling, providing a new way to probe neutrino mass mechanisms at future colliders.

Contribution

It presents the first detailed study of one-loop corrections to the triple Higgs coupling in a realistic inverse seesaw model, considering all relevant constraints.

Findings

Deviations up to +30% in the triple Higgs coupling from the Standard Model.

Deviations are within HL-LHC sensitivity but clearly detectable at ILC or FCC-hh.

Heavy neutrinos can be effectively probed through Higgs self-coupling measurements.

Abstract

The measure of the triple Higgs coupling is one of the major goals of the high-luminosity run of the CERN Large Hadron Collider (HL-LHC) as well as the future colliders, either leptonic such as the International Linear Collider (ILC) or hadronic such as the 100 TeV Future Circular Collider in hadron-hadron mode (FCC-hh). We have recently proposed this observable as a test of neutrino mass generating mechanisms in a regime where heavy sterile neutrino masses are hard to be probed otherwise. We present in this article a study of the one-loop corrected triple Higgs coupling in the inverse seesaw model, taking into account all relevant constraints on the model. This is the first study of the impact on the triple Higgs coupling of heavy neutrinos in a realistic, renormalizable neutrino mass model. We obtain deviations from the Standard Model as large as to $\sim +30\%$ that are at the current limit of the HL-LHC sensitivity, but would be clearly visible at the ILC or at the FCC-hh.